Scaffold-jack



UNITED STATES CARL HJALMAR LARSSON, OE SEATTLE, NASHINGTON.

SCAFF OLD JACK.

Specification of Letters latent.

Patented Oct. 18, 1921.

Application filed January 2, 1920. Serial No. 348,819.

l '0 all whom it may concern:

Be it known that I, CARL I'IJALMAR Lane I sort, a subject of the King ofSweden, and

resident of the city of Seattle, county of King, and State ofWashington, have invented certain new and useful Improvements inScaffold-Jacks, of which the following is a specification.

My invention relates to a scaffold jack which is particularly adaptedfor use in connection with the scaffolding which is stand ard inship-yards.

One object of my invention is to produce a jack which may be used tolift the planks forming the scaffolding platform or the lat eral spallwhich supports these planks, which jack may be supported either from theuprights themselves or from a lower spall or platform plank, as may befound desirable.

.aIlOillQl object of my invention is to produce a scaffold jack which,in the form in which it would usually be used, would be suflicientlylight in construction that it might be manipulated by one man.

My invention comprises the novel parts and combinations thereof whichare shown in the accompanying drawings, described in the specifications,and particularly defined by the claims terminating the same.

In the accompanying drawings I have shown my invention in the form whichis now preferred by me.

Figure l is an elevation of my invention complete, parts being brokenaway, and shown in section.

Fig. 2 is an elevation of my invention looking at it from the side whichis designed to be attached to the uprights.

Fig. 3 is a perspective of a standa d shipyard scafiolding illustratingmy invention in use.

The standard shipyard scaffolding is composed of uprights formed of twotimbers 5 spaced apartand placed in pairs of two, forward and rear, asshown in Fig. 3., and cross-braced with small timbers 50. In these pairsof uprights are supported the spalls 51. These are generallysupported bymeans of pins 52 which pass through holes 53 in the uprights and beneaththe spalls or beneath their forward ends and above their rear ends, asthe occasion may require. The pairs of uprights 5 are braced one fromthe other by means of braces 54 between the rear uprights of each pair.

The forward ends of the spalls 51 are left projecting forward and uponthem are supported the planks 55 which form a scaffold platform. Theseplanks are generally quite heavy, 2"; :12 planks being the standardsize, and gene" v three of these are supported side by s upon theprojecting'ends of the spalls.

In constructing a ship it is necessary to change the position of theplanks 55 and the spalls 51 frequently as the construction progresses,the planks 55 of one platform must be piled one upon the other andshoved back toward the uprights to give space for work- 1 latform below.The di permit the requisite freedom of movement. This method ofprocedure is illustrated at the right of Fig. 8. As constructionprogresses upwarl the platforms mu be raised for the rious gangs ofwornmen it is for doing this heavy lif ing my jack is designed. thiswork is performed by a number of men working together and known asscaffold riggers. the use of my invention this scaffold may be done byone man instead of several.

There are often times in such work when it is impossible to secure afirm support beneath a jack and for that reason I provide means wherebmy jack may be supported from the uprights. is herein shown the nut 1,which has the screw 2 threaded therein, is provided witi a pair of arms.The upper arm 10 is provided with means for engaging the rear of anupright 5, as the laterally projecting finger 11. The lower arm 19 isprovided with means for engaging the forward face of'the upright 5. ThisI have shown as the projecting finger IS. I prefer also that the arm 19should have a fin 7 which is adapted to engage with the side face of theupright. The fingers 11, 18, and 17, may be provided with short pins orcallrs which are adapted to project into the wooden upright to provide amore secure grip thereon. I prefer also that the arms 10 and 19 and ti efingers secured to these arms should be so formed that they may heinterchangeably engaged with either side face of the upright. The reasonfor this is that it might be found impossible at times to secure thefinger to the upright at the desired position on account of interferonceby the braces 50. In this case the arms Ordinarily this length theentire platform may be lifted without disturbing its arrangement andwithout p1ling up the boards, and the spall can then be raised orlowered while the pick 'supports the planks. The arm 21 may also beprovided with callrs as shown, for engagmgthe wooden planks. it may beturned horizontally at any angle desired and may be engaged beneath thespall 51 to lift the platform in this manner.

At times it mi 'ht be found desirable to 1 h support the jitC'K from aplatrorm or spell beneath it. I. have, therefore, provided an attachmentwhich nus a pair of le s 3 prod ce vided with feet 30 for supporting;the from a platfo m. -The legs 3 as herein shown are supported in crossarm 31 which is screwed tut-on the outside of the nut l at 32 or isSQ('.H1\,.4 thereto in any other suitable manner. Supplemental toes 33are mounted upon the legs these being); adapted to en- 'age upon theedges of the planks or spalls.

ll prefer that they he pivoted upon the to swine; laterallv thereon sothat they may be swungout of the way when not in use.

If desired ratchet means may be employed for turning the scr-w 2. Asshown herein this consists of the arm 2-{t pivotally mounted upon thelower end of the screw and our rying a spring pressed vpawl 25 whichonwith a ratchet pinion secured upon thescrew. For convenience inhandlingthe device 1 may provide a. handle 13 upon the nut. I may alsoattach a chain and hook 14 to the nut, by means of which the jack may heshuns; in the scaffoldingwhen not in use.

What I claim as my invention is:

1. Means for rrising or lowering scaffolding platforms comprising; anattachment member and an elevator member engaged therewith andvertically movable therein, and supporting means for said attachmentmember comprising an upper arm having laterally projecting fingersengageable' with the rear face of a scaffold upright.- and a lower armhaving laterally-projecting fin- ;gers en 'aeeable with the forward faceof the upright 2'. Means for raising or lowering scaffolding meansadapted to be secur ing platforms comprising an attachment member and anelevator member engaged therewith and vertically movable therein, andsupporting means; for said attachment member comprising an upper armhaving laterally-projecting fingers engageable with the rear face of ascaffold upright; and a lower arm having laterally-projecting fingersengageable with the forward face of the upright, said lower arm havingalso a finger engageable with a side face of theupright, said supportingarms and fingers be ing interchangeably engageable with opposite sidefaces of the upright.

3. A scaffold jack comprising a nut and a screw threaded therein ascaifold support upon the upper end of said screw, means for supportingsaid nut by engagement with a scaffold uprig ;ht and supplementalsupporting means adapted to be secured to said nut and to support thejack from a'horizontal portion of the scaifold.

4e. A scalfold jack comprising 'anut a sore threaded therein, a scaffolupon the upper end of id screw supporti said nut by engagement wlscs'fold n rightand supplemental support ing; means adapted to besecured to said nu and com rising legs depending from the nu and havingseries of laterally projecting t adapted to engage horizontal portionsof scalfold. y p 5, scaffold cl; comprisin a nut and a screw threadedthereiin a s told support upon the upper end of said screw, means forsupporting said nut by engagement with a scaffold upright, andSupplemental supportto said nut and compi l pending ;;om the nuthavingseries ot terally projecting toes adapted to engage horizontalportions of the scaffold said toes being pivotally mounted upon saidlegs; 1

6. In ascaiiold jar-ha nut pro means for supporting it Q right,comprising an upper arm havi u fingers laterally projecting in oppositedirections, either finger being; adapted to engage the rear face of ascaffold uprightV and a f CARL HJALMAR LARSSOE.

